Trump praised his country's close relationship and trade surplus with Australia, saying "we'll be doing something with them".

There would be a reduction in tariffs for countries that "treat us fairly", he said but said "many of the countries that treat us the worst on trade and on military are our allies". He had earlier in the day singled out Germany for criticism.

"I will seek more clarity on this issue in the days to come. Looking forward to meeting USTR Lighthizer in Brussels on Sat to discuss."

The UK would be affected by any tariffs applied to the EU - at least until after it officially leaves the bloc.

This morning, speaking at an event organised by the German Marshall Fund, she added:“It is not crystal clear on what the president said yesterday, so we will have to seek further clarity.

“We hope that we can get clarity that the EU is excluded from this, if not we have been clear that we don’t think this is compatible with the WTO, so we will go to the WTO, possibly within some other friends.”